The purpose of this project is to analyze and report on previously collected data concerning the Mexican American extended family. The data include a survey of 381 Mexican Americans in three southern California cities and in-depth interviews with 24 Mexican American families. Comparative survey data for 163 Anglo Americans are also to be used. Contrary to assumptions of previous researchers, preliminary data analysis indicates that the Mexican Ameican extended family remains viable in urban areas and, in fact, grows larger and more integrated with acculturation and social and economic assimilation. Mexican American family patterns remain distinct from those of Anglo Americans generation after generation. It is proposed that the erroneous assumptions of earlier researchers are a product of an assimilationist model of culture change and that the findings are better interpreted using a model of sociocultural pluralism. Statistical analysis of the data will produce: descriptive statistics concerning real and fictive kin for the entire sample of Mexican Americans; the extent of variation in real and fictive kin between Mexican American generations, levels of acculturation and ethnic identity, and SES levels; comparisons between Anglo and Mexican American extended families; and the relationship between extended familism among Mexican Americans and traits of urbanism, acculturation, and social and economic assimilation. The results will permit a reevaluation of change and persistence in the Mexican American extended family. The findings will be useful in understanding the Mexican American extended family as mental health support system.